src/librustdoc/clean/inline.rs

   1 // Copyright 2012-2013 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 //! Support for inlining external documentation into the current AST.
  12
  13 use std::iter::once;
  14
  15 use syntax::ast;
  16 use syntax::ext::base::MacroKind;
  17 use syntax_pos::Span;
  18
  19 use rustc::hir;
  20 use rustc::hir::def::{Def, CtorKind};
  21 use rustc::hir::def_id::DefId;
  22 use rustc::middle::cstore::LoadedMacro;
  23 use rustc::ty;
  24 use rustc::util::nodemap::FxHashSet;
  25
  26 use core::{DocContext, DocAccessLevels};
  27 use doctree;
  28 use clean::{self, GetDefId, ToSource, get_auto_traits_with_def_id};
  29
  30 use super::Clean;
  31
  32 /// Attempt to inline a definition into this AST.
  33 ///
  34 /// This function will fetch the definition specified, and if it is
  35 /// from another crate it will attempt to inline the documentation
  36 /// from the other crate into this crate.
  37 ///
  38 /// This is primarily used for `pub use` statements which are, in general,
  39 /// implementation details. Inlining the documentation should help provide a
  40 /// better experience when reading the documentation in this use case.
  41 ///
  42 /// The returned value is `None` if the definition could not be inlined,
  43 /// and `Some` of a vector of items if it was successfully expanded.
  44 pub fn try_inline(cx: &DocContext, def: Def, name: ast::Name, visited: &mut FxHashSet<DefId>)
  45                   -> Option<Vec<clean::Item>> {
  46     if def == Def::Err { return None }
  47     let did = def.def_id();
  48     if did.is_local() { return None }
  49     let mut ret = Vec::new();
  50     let inner = match def {
  51         Def::Trait(did) => {
  52             record_extern_fqn(cx, did, clean::TypeKind::Trait);
  53             ret.extend(build_impls(cx, did, false));
  54             clean::TraitItem(build_external_trait(cx, did))
  55         }
  56         Def::Fn(did) => {
  57             record_extern_fqn(cx, did, clean::TypeKind::Function);
  58             clean::FunctionItem(build_external_function(cx, did))
  59         }
  60         Def::Struct(did) => {
  61             record_extern_fqn(cx, did, clean::TypeKind::Struct);
  62             ret.extend(build_impls(cx, did, true));
  63             clean::StructItem(build_struct(cx, did))
  64         }
  65         Def::Union(did) => {
  66             record_extern_fqn(cx, did, clean::TypeKind::Union);
  67             ret.extend(build_impls(cx, did, true));
  68             clean::UnionItem(build_union(cx, did))
  69         }
  70         Def::TyAlias(did) => {
  71             record_extern_fqn(cx, did, clean::TypeKind::Typedef);
  72             ret.extend(build_impls(cx, did, false));
  73             clean::TypedefItem(build_type_alias(cx, did), false)
  74         }
  75         Def::Enum(did) => {
  76             record_extern_fqn(cx, did, clean::TypeKind::Enum);
  77             ret.extend(build_impls(cx, did, true));
  78             clean::EnumItem(build_enum(cx, did))
  79         }
  80         Def::TyForeign(did) => {
  81             record_extern_fqn(cx, did, clean::TypeKind::Foreign);
  82             ret.extend(build_impls(cx, did, false));
  83             clean::ForeignTypeItem
  84         }
  85         // Never inline enum variants but leave them shown as re-exports.
  86         Def::Variant(..) => return None,
  87         // Assume that enum variants and struct types are re-exported next to
  88         // their constructors.
  89         Def::VariantCtor(..) |
  90         Def::StructCtor(..) => return Some(Vec::new()),
  91         Def::Mod(did) => {
  92             record_extern_fqn(cx, did, clean::TypeKind::Module);
  93             clean::ModuleItem(build_module(cx, did, visited))
  94         }
  95         Def::Static(did, mtbl) => {
  96             record_extern_fqn(cx, did, clean::TypeKind::Static);
  97             clean::StaticItem(build_static(cx, did, mtbl))
  98         }
  99         Def::Const(did) => {
 100             record_extern_fqn(cx, did, clean::TypeKind::Const);
 101             clean::ConstantItem(build_const(cx, did))
 102         }
 103         // FIXME(misdreavus): if attributes/derives come down here we should probably document them
 104         // separately
 105         Def::Macro(did, MacroKind::Bang) => {
 106             record_extern_fqn(cx, did, clean::TypeKind::Macro);
 107             if let Some(mac) = build_macro(cx, did, name) {
 108                 clean::MacroItem(mac)
 109             } else {
 110                 return None;
 111             }
 112         }
 113         _ => return None,
 114     };
 115     cx.renderinfo.borrow_mut().inlined.insert(did);
 116     ret.push(clean::Item {
 117         source: cx.tcx.def_span(did).clean(cx),
 118         name: Some(name.clean(cx)),
 119         attrs: load_attrs(cx, did),
 120         inner,
 121         visibility: Some(clean::Public),
 122         stability: cx.tcx.lookup_stability(did).clean(cx),
 123         deprecation: cx.tcx.lookup_deprecation(did).clean(cx),
 124         def_id: did,
 125     });
 126     Some(ret)
 127 }
 128
 129 pub fn try_inline_glob(cx: &DocContext, def: Def, visited: &mut FxHashSet<DefId>)
 130     -> Option<Vec<clean::Item>>
 131 {
 132     if def == Def::Err { return None }
 133     let did = def.def_id();
 134     if did.is_local() { return None }
 135
 136     match def {
 137         Def::Mod(did) => {
 138             let m = build_module(cx, did, visited);
 139             Some(m.items)
 140         }
 141         // glob imports on things like enums aren't inlined even for local exports, so just bail
 142         _ => None,
 143     }
 144 }
 145
 146 pub fn load_attrs(cx: &DocContext, did: DefId) -> clean::Attributes {
 147     cx.tcx.get_attrs(did).clean(cx)
 148 }
 149
 150 /// Record an external fully qualified name in the external_paths cache.
 151 ///
 152 /// These names are used later on by HTML rendering to generate things like
 153 /// source links back to the original item.
 154 pub fn record_extern_fqn(cx: &DocContext, did: DefId, kind: clean::TypeKind) {
 155     if did.is_local() {
 156         debug!("record_extern_fqn(did={:?}, kind+{:?}): def_id is local, aborting", did, kind);
 157         return;
 158     }
 159
 160     let crate_name = cx.tcx.crate_name(did.krate).to_string();
 161     let relative = cx.tcx.def_path(did).data.into_iter().filter_map(|elem| {
 162         // extern blocks have an empty name
 163         let s = elem.data.to_string();
 164         if !s.is_empty() {
 165             Some(s)
 166         } else {
 167             None
 168         }
 169     });
 170     let fqn = if let clean::TypeKind::Macro = kind {
 171         vec![crate_name, relative.last().unwrap()]
 172     } else {
 173         once(crate_name).chain(relative).collect()
 174     };
 175     cx.renderinfo.borrow_mut().external_paths.insert(did, (fqn, kind));
 176 }
 177
 178 pub fn build_external_trait(cx: &DocContext, did: DefId) -> clean::Trait {
 179     let auto_trait = cx.tcx.trait_def(did).has_auto_impl;
 180     let trait_items = cx.tcx.associated_items(did).map(|item| item.clean(cx)).collect();
 181     let predicates = cx.tcx.predicates_of(did);
 182     let generics = (cx.tcx.generics_of(did), &predicates).clean(cx);
 183     let generics = filter_non_trait_generics(did, generics);
 184     let (generics, supertrait_bounds) = separate_supertrait_bounds(generics);
 185     let is_spotlight = load_attrs(cx, did).has_doc_flag("spotlight");
 186     let is_auto = cx.tcx.trait_is_auto(did);
 187     clean::Trait {
 188         auto: auto_trait,
 189         unsafety: cx.tcx.trait_def(did).unsafety,
 190         generics,
 191         items: trait_items,
 192         bounds: supertrait_bounds,
 193         is_spotlight,
 194         is_auto,
 195     }
 196 }
 197
 198 fn build_external_function(cx: &DocContext, did: DefId) -> clean::Function {
 199     let sig = cx.tcx.fn_sig(did);
 200
 201     let constness = if cx.tcx.is_const_fn(did) {
 202         hir::Constness::Const
 203     } else {
 204         hir::Constness::NotConst
 205     };
 206
 207     let predicates = cx.tcx.predicates_of(did);
 208     clean::Function {
 209         decl: (did, sig).clean(cx),
 210         generics: (cx.tcx.generics_of(did), &predicates).clean(cx),
 211         header: hir::FnHeader {
 212             unsafety: sig.unsafety(),
 213             abi: sig.abi(),
 214             constness,
 215             asyncness: hir::IsAsync::NotAsync,
 216         }
 217     }
 218 }
 219
 220 fn build_enum(cx: &DocContext, did: DefId) -> clean::Enum {
 221     let predicates = cx.tcx.predicates_of(did);
 222
 223     clean::Enum {
 224         generics: (cx.tcx.generics_of(did), &predicates).clean(cx),
 225         variants_stripped: false,
 226         variants: cx.tcx.adt_def(did).variants.clean(cx),
 227     }
 228 }
 229
 230 fn build_struct(cx: &DocContext, did: DefId) -> clean::Struct {
 231     let predicates = cx.tcx.predicates_of(did);
 232     let variant = cx.tcx.adt_def(did).non_enum_variant();
 233
 234     clean::Struct {
 235         struct_type: match variant.ctor_kind {
 236             CtorKind::Fictive => doctree::Plain,
 237             CtorKind::Fn => doctree::Tuple,
 238             CtorKind::Const => doctree::Unit,
 239         },
 240         generics: (cx.tcx.generics_of(did), &predicates).clean(cx),
 241         fields: variant.fields.clean(cx),
 242         fields_stripped: false,
 243     }
 244 }
 245
 246 fn build_union(cx: &DocContext, did: DefId) -> clean::Union {
 247     let predicates = cx.tcx.predicates_of(did);
 248     let variant = cx.tcx.adt_def(did).non_enum_variant();
 249
 250     clean::Union {
 251         struct_type: doctree::Plain,
 252         generics: (cx.tcx.generics_of(did), &predicates).clean(cx),
 253         fields: variant.fields.clean(cx),
 254         fields_stripped: false,
 255     }
 256 }
 257
 258 fn build_type_alias(cx: &DocContext, did: DefId) -> clean::Typedef {
 259     let predicates = cx.tcx.predicates_of(did);
 260
 261     clean::Typedef {
 262         type_: cx.tcx.type_of(did).clean(cx),
 263         generics: (cx.tcx.generics_of(did), &predicates).clean(cx),
 264     }
 265 }
 266
 267 pub fn build_impls(cx: &DocContext, did: DefId, auto_traits: bool) -> Vec<clean::Item> {
 268     let tcx = cx.tcx;
 269     let mut impls = Vec::new();
 270
 271     for &did in tcx.inherent_impls(did).iter() {
 272         build_impl(cx, did, &mut impls);
 273     }
 274
 275     if auto_traits {
 276         let auto_impls = get_auto_traits_with_def_id(cx, did);
 277         let mut renderinfo = cx.renderinfo.borrow_mut();
 278         let new_impls: Vec<clean::Item> = auto_impls.into_iter()
 279             .filter(|i| renderinfo.inlined.insert(i.def_id)).collect();
 280
 281         impls.extend(new_impls);
 282     }
 283
 284     // If this is the first time we've inlined something from another crate, then
 285     // we inline *all* impls from all the crates into this crate. Note that there's
 286     // currently no way for us to filter this based on type, and we likely need
 287     // many impls for a variety of reasons.
 288     //
 289     // Primarily, the impls will be used to populate the documentation for this
 290     // type being inlined, but impls can also be used when generating
 291     // documentation for primitives (no way to find those specifically).
 292     if cx.populated_all_crate_impls.get() {
 293         return impls;
 294     }
 295
 296     cx.populated_all_crate_impls.set(true);
 297
 298     for &cnum in tcx.crates().iter() {
 299         for did in tcx.all_trait_implementations(cnum).iter() {
 300             build_impl(cx, *did, &mut impls);
 301         }
 302     }
 303
 304     // Also try to inline primitive impls from other crates.
 305     let lang_items = tcx.lang_items();
 306     let primitive_impls = [
 307         lang_items.isize_impl(),
 308         lang_items.i8_impl(),
 309         lang_items.i16_impl(),
 310         lang_items.i32_impl(),
 311         lang_items.i64_impl(),
 312         lang_items.i128_impl(),
 313         lang_items.usize_impl(),
 314         lang_items.u8_impl(),
 315         lang_items.u16_impl(),
 316         lang_items.u32_impl(),
 317         lang_items.u64_impl(),
 318         lang_items.u128_impl(),
 319         lang_items.f32_impl(),
 320         lang_items.f64_impl(),
 321         lang_items.f32_runtime_impl(),
 322         lang_items.f64_runtime_impl(),
 323         lang_items.char_impl(),
 324         lang_items.str_impl(),
 325         lang_items.slice_impl(),
 326         lang_items.slice_u8_impl(),
 327         lang_items.str_alloc_impl(),
 328         lang_items.slice_alloc_impl(),
 329         lang_items.slice_u8_alloc_impl(),
 330         lang_items.const_ptr_impl(),
 331         lang_items.mut_ptr_impl(),
 332     ];
 333
 334     for def_id in primitive_impls.iter().filter_map(|&def_id| def_id) {
 335         if !def_id.is_local() {
 336             build_impl(cx, def_id, &mut impls);
 337
 338             let auto_impls = get_auto_traits_with_def_id(cx, def_id);
 339             let mut renderinfo = cx.renderinfo.borrow_mut();
 340
 341             let new_impls: Vec<clean::Item> = auto_impls.into_iter()
 342                 .filter(|i| renderinfo.inlined.insert(i.def_id)).collect();
 343
 344             impls.extend(new_impls);
 345         }
 346     }
 347
 348     impls
 349 }
 350
 351 pub fn build_impl(cx: &DocContext, did: DefId, ret: &mut Vec<clean::Item>) {
 352     if !cx.renderinfo.borrow_mut().inlined.insert(did) {
 353         return
 354     }
 355
 356     let attrs = load_attrs(cx, did);
 357     let tcx = cx.tcx;
 358     let associated_trait = tcx.impl_trait_ref(did);
 359
 360     // Only inline impl if the implemented trait is
 361     // reachable in rustdoc generated documentation
 362     if let Some(traitref) = associated_trait {
 363         if !cx.access_levels.borrow().is_doc_reachable(traitref.def_id) {
 364             return
 365         }
 366     }
 367
 368     let for_ = tcx.type_of(did).clean(cx);
 369
 370     // Only inline impl if the implementing type is
 371     // reachable in rustdoc generated documentation
 372     if let Some(did) = for_.def_id() {
 373         if !cx.access_levels.borrow().is_doc_reachable(did) {
 374             return
 375         }
 376     }
 377
 378     let predicates = tcx.predicates_of(did);
 379     let trait_items = tcx.associated_items(did).filter_map(|item| {
 380         if associated_trait.is_some() || item.vis == ty::Visibility::Public {
 381             Some(item.clean(cx))
 382         } else {
 383             None
 384         }
 385     }).collect::<Vec<_>>();
 386     let polarity = tcx.impl_polarity(did);
 387     let trait_ = associated_trait.clean(cx).map(|bound| {
 388         match bound {
 389             clean::GenericBound::TraitBound(polyt, _) => polyt.trait_,
 390             clean::GenericBound::Outlives(..) => unreachable!(),
 391         }
 392     });
 393     if trait_.def_id() == tcx.lang_items().deref_trait() {
 394         super::build_deref_target_impls(cx, &trait_items, ret);
 395     }
 396     if let Some(trait_did) = trait_.def_id() {
 397         record_extern_trait(cx, trait_did);
 398     }
 399
 400     let provided = trait_.def_id().map(|did| {
 401         tcx.provided_trait_methods(did)
 402            .into_iter()
 403            .map(|meth| meth.ident.to_string())
 404            .collect()
 405     }).unwrap_or(FxHashSet());
 406
 407     ret.push(clean::Item {
 408         inner: clean::ImplItem(clean::Impl {
 409             unsafety: hir::Unsafety::Normal,
 410             generics: (tcx.generics_of(did), &predicates).clean(cx),
 411             provided_trait_methods: provided,
 412             trait_,
 413             for_,
 414             items: trait_items,
 415             polarity: Some(polarity.clean(cx)),
 416             synthetic: false,
 417             blanket_impl: None,
 418         }),
 419         source: tcx.def_span(did).clean(cx),
 420         name: None,
 421         attrs,
 422         visibility: Some(clean::Inherited),
 423         stability: tcx.lookup_stability(did).clean(cx),
 424         deprecation: tcx.lookup_deprecation(did).clean(cx),
 425         def_id: did,
 426     });
 427 }
 428
 429 fn build_module(cx: &DocContext, did: DefId, visited: &mut FxHashSet<DefId>) -> clean::Module {
 430     let mut items = Vec::new();
 431     fill_in(cx, did, &mut items, visited);
 432     return clean::Module {
 433         items,
 434         is_crate: false,
 435     };
 436
 437     fn fill_in(cx: &DocContext, did: DefId, items: &mut Vec<clean::Item>,
 438                visited: &mut FxHashSet<DefId>) {
 439         // If we're re-exporting a re-export it may actually re-export something in
 440         // two namespaces, so the target may be listed twice. Make sure we only
 441         // visit each node at most once.
 442         for &item in cx.tcx.item_children(did).iter() {
 443             let def_id = item.def.def_id();
 444             if item.vis == ty::Visibility::Public {
 445                 if did == def_id || !visited.insert(def_id) { continue }
 446                 if let Some(i) = try_inline(cx, item.def, item.ident.name, visited) {
 447                     items.extend(i)
 448                 }
 449             }
 450         }
 451     }
 452 }
 453
 454 pub fn print_inlined_const(cx: &DocContext, did: DefId) -> String {
 455     cx.tcx.rendered_const(did)
 456 }
 457
 458 fn build_const(cx: &DocContext, did: DefId) -> clean::Constant {
 459     clean::Constant {
 460         type_: cx.tcx.type_of(did).clean(cx),
 461         expr: print_inlined_const(cx, did)
 462     }
 463 }
 464
 465 fn build_static(cx: &DocContext, did: DefId, mutable: bool) -> clean::Static {
 466     clean::Static {
 467         type_: cx.tcx.type_of(did).clean(cx),
 468         mutability: if mutable {clean::Mutable} else {clean::Immutable},
 469         expr: "\n\n\n".to_string(), // trigger the "[definition]" links
 470     }
 471 }
 472
 473 fn build_macro(cx: &DocContext, did: DefId, name: ast::Name) -> Option<clean::Macro> {
 474     let imported_from = cx.tcx.original_crate_name(did.krate);
 475     let def = match cx.cstore.load_macro_untracked(did, cx.sess()) {
 476         LoadedMacro::MacroDef(macro_def) => macro_def,
 477         // FIXME(jseyfried): document proc macro re-exports
 478         LoadedMacro::ProcMacro(..) => return None,
 479     };
 480
 481     let matchers: hir::HirVec<Span> = if let ast::ItemKind::MacroDef(ref def) = def.node {
 482         let tts: Vec<_> = def.stream().into_trees().collect();
 483         tts.chunks(4).map(|arm| arm[0].span()).collect()
 484     } else {
 485         unreachable!()
 486     };
 487
 488     let source = format!("macro_rules! {} {{\n{}}}",
 489                          name.clean(cx),
 490                          matchers.iter().map(|span| {
 491                              format!("    {} => {{ ... }};\n", span.to_src(cx))
 492                          }).collect::<String>());
 493
 494     Some(clean::Macro {
 495         source,
 496         imported_from: Some(imported_from).clean(cx),
 497     })
 498 }
 499
 500 /// A trait's generics clause actually contains all of the predicates for all of
 501 /// its associated types as well. We specifically move these clauses to the
 502 /// associated types instead when displaying, so when we're generating the
 503 /// generics for the trait itself we need to be sure to remove them.
 504 /// We also need to remove the implied "recursive" Self: Trait bound.
 505 ///
 506 /// The inverse of this filtering logic can be found in the `Clean`
 507 /// implementation for `AssociatedType`
 508 fn filter_non_trait_generics(trait_did: DefId, mut g: clean::Generics) -> clean::Generics {
 509     for pred in &mut g.where_predicates {
 510         match *pred {
 511             clean::WherePredicate::BoundPredicate {
 512                 ty: clean::Generic(ref s),
 513                 ref mut bounds
 514             } if *s == "Self" => {
 515                 bounds.retain(|bound| {
 516                     match *bound {
 517                         clean::GenericBound::TraitBound(clean::PolyTrait {
 518                             trait_: clean::ResolvedPath { did, .. },
 519                             ..
 520                         }, _) => did != trait_did,
 521                         _ => true
 522                     }
 523                 });
 524             }
 525             _ => {}
 526         }
 527     }
 528
 529     g.where_predicates.retain(|pred| {
 530         match *pred {
 531             clean::WherePredicate::BoundPredicate {
 532                 ty: clean::QPath {
 533                     self_type: box clean::Generic(ref s),
 534                     trait_: box clean::ResolvedPath { did, .. },
 535                     name: ref _name,
 536                 }, ref bounds
 537             } => !(*s == "Self" && did == trait_did) && !bounds.is_empty(),
 538             _ => true,
 539         }
 540     });
 541     g
 542 }
 543
 544 /// Supertrait bounds for a trait are also listed in the generics coming from
 545 /// the metadata for a crate, so we want to separate those out and create a new
 546 /// list of explicit supertrait bounds to render nicely.
 547 fn separate_supertrait_bounds(mut g: clean::Generics)
 548                               -> (clean::Generics, Vec<clean::GenericBound>) {
 549     let mut ty_bounds = Vec::new();
 550     g.where_predicates.retain(|pred| {
 551         match *pred {
 552             clean::WherePredicate::BoundPredicate {
 553                 ty: clean::Generic(ref s),
 554                 ref bounds
 555             } if *s == "Self" => {
 556                 ty_bounds.extend(bounds.iter().cloned());
 557                 false
 558             }
 559             _ => true,
 560         }
 561     });
 562     (g, ty_bounds)
 563 }
 564
 565 pub fn record_extern_trait(cx: &DocContext, did: DefId) {
 566     if cx.external_traits.borrow().contains_key(&did) ||
 567         cx.active_extern_traits.borrow().contains(&did)
 568     {
 569         return;
 570     }
 571
 572     cx.active_extern_traits.borrow_mut().push(did);
 573
 574     let trait_ = build_external_trait(cx, did);
 575
 576     cx.external_traits.borrow_mut().insert(did, trait_);
 577     cx.active_extern_traits.borrow_mut().remove_item(&did);
 578 }